Element structure for electron devices



Nov. 6, 1934. w. L. KRAHL ELEMENT STRUCTURE FOR ELECTRON DEVICES Filed Jan. 25. 1930 INVENTOR WALTER L HRH 1'4 ATTORNEY Patented Nov. 6, 1934 UNiTE STATES l ttt ttt sea ELEMENT STRUCTURE FOR ELECTRON DEVICES Application January 25, 1930, Serial No. 423,505

16 Claims.

This invention relates to electron devices and constitutes an improvement over the construcion shown in my application Serial No. 406,243, entitled Vacuum tube assembly, filed November i 11, 1929.

In exhausting the air from electron devices it is necessary to heat the elements in order to drive out any occluded gases. Normally the exhausting process is carried over a relatively long interval of time and the temperature of the various elements does not need to be raised above the vaporization point of the metal forming the element. However, in an automatic machine for carrying on this exhausting process more moval of all the occluded gases during the time the device is connected to the machine, it is necessary to raise the temperature of the elements.

I have found that when temperature of the elements of the structure described in the above mentioned application is so raised the cathode is heated above its vaporization point so that some of the metal of the cathode disintegrates, causing a film of the metal to form on the insulator parts of the device producing leaks between the various elements.

It is therefore one of the objects of the present invention to provide a unitary element structure for an electron device in which the ele ments may be heated to a relatively high degree without causing the elements to disintegrate.

Another object of the invention is to provide a means to cool the ends of the cathode.

Another object of the invention is to provide a unitary element structure which has greater rigidity and therefore less liability for the parts to move with respect to one another.

Other objects of the invention and objects relating particularly to the construction of the various parts and the method of assembling them will be apparent as the description of the invention proceeds.

The invention has been illustrated in the accompanying drawing in which:

Fig. 1 is a front sectional elevation of an electron device embodying the invention;

Fig. 2 is a side sectional View. of the elements taken on the line 22 of Fig. 1;

Fig. 3 is a plan View of the element structure;

Fig. 4-. is a sectional plan View taken on the line 44 of Fig. 1; and

Fig. 5 is a sectional plan view of the elements taken on the line 55 of Fig. 1.

Referring now more specifically to Fig. 1 the 1 speed is made, and in order to insure the reinvention is shown in connection with an electron device having an envelope 10 shown in dot and dash lines and mounted upon the usual base 11 which supports the contact terminals for making the necessary connections to an outside circuit. A stem tube 12 is formed integral with the envelope l0 and stands up within the envelope and a press 13 is provided at the top of the stem to seal the various connections into the device and form a support for the elements.

The elements of the device comprise an anode 14, a grid 15, a cathode 16, and a heater 1'7 for the cathode.

The anode 14 may be made of perforated metal bent in the form of a cylinder and having flanges 18 extending radially and outwardly on one side thereof with bent edges to form grooves 19 to cooperate with a support as will be hereinafter described. The anode may be provided with extended arcuate portions 20 at each end thereof spaced apart and diametrically opposite each other. The extended portions may each be provided at the corners thereof with fingers 21 which are adapted to secure the anode to two spaced apart insulator plates 22 and 23.

The insulator plates 22 and 23 are made exactly alike and are substantially rectangular with rounded ends, as indicated, and are each provided in the center thereof with a square hole 22a and a pair of small holes 23a spaced apart one on each side of the square hole 220, and lying along the longitudinal axis of the insulator plate. On each side of this longitudinal axis I providea pair of openings 24 spaced apart and arranged symmetrically with respect to both the longitudinal and lateral axes of the insulating plate. These openings are provided with surfaces 25 which are tangential to a circle having the same diameter as the anode 14 and the center thereof coincident with the center of the square opening 22a.

The upper insulator 22 is adapted to rest upon the extended portions 20 at the top of the anode with the fingers 21 extending up. through the openings 24 and being bent over on the topof the insulator against the surfaces 25 as is clearly evident from an inspection of the plan View of the elements as shown in Fig. 3. In like manner the insulator 23 is positioned at the bottom of the anode 14, the fingers 21 at that end extending through the openings 24 and being bent over the bottom as indicated in Fig. 5. Thus the insulators 22 and 23 are securely held upon the anode.

The grid 15 comprises the usual helix of wire mounted upon a support rod 26 which extends through one of the openings 23a in each plate.

In each of the insulators 22 and 23 I provide slots 27 lying on the longitudinal axis of the insulator and spaced from the center outwardly beyond the openings 23a. Each of the slots 2'? has a rounded outer end as at 28 and an enlarged inner end 29. A strap 30 is bent around the grid supporting post 26 just above the lower insulator 23 and the two sides of the strap extend outwardly to a point over the enlarged portion 29 of the slot 27. The ends of the strap 30 are provided with lateral extension members 31 which are grooved as indicated to form a socket when placed together, and extend downwardly through the enlargement 29 in the slot 2'7. This forms a means to prevent the grid post 26 from rotating in the opening 23a and, therefore, prevents the grid from getting out of alignment with respect to the anode.

The cathode 16 is preferably a cylinder of nickel and is positioned within the grid with its ends extending through the square openings 22a in the insulators 22 and 23. The cathode 16 is provided at its lower end with a strap 32 which may be welded to the end of the cathode just below the insulating plate 23 and the ends of the strap are adapted to extend outwardly along the longitudinal axis of the insulator plate and beneath the slot 27 on the opposite side of the insulator plate from the strap 30 which is attached to the grid support 26. The strap 32 is provided with upwardly extending fingers 33 which pass through the slot 27 and are bent over against the other side of the insulator plate 23 thus holding the strap 32 in position upon the insulator plate and preventing the cathode 16 from rotating. The extreme ends of the strap- 32 are grooved as at 34 to form a socket for a supporting post which will be hereinafter described.

Thus defined the elements are mounted in a unitary structure the anode securing the two spaced insulator plates and these plates securing the grid and cathode in spaced relation with respect to the anode. In order to mount the structure in an electron device or thermionic tube I provide the press 13 with a pair of spaced apart, relatively long supporting posts 35 and 36, one at each end thereoi. The element structure is then placed upon these support posts, the post 35 passing through the rounded ends 28 of the slots 27 in both the plates 22 and 23 and the post 36 passing through the corresponding ends of the slots on the other end of the insulating plates. The structure may be slid down on these posts until the desired position is reached whereupon the ends 34 of the strap 32 may be welded to the post 35 thereby anchoring the element structure and in addition the grooves 19 in the anode flanges 18 may be welded to the post 36 which extends between these flanges, as is clearly indicated in Figs. 1 and 4.

A short support post 3'? is also providedrin the press 13 adjacent the post 36 and this post is inserted in the socket formed by the extended members 31 of the grid strap 30 and these members may be welded to the post 37 thereby form ing an additional anchor for the unitary element structure and especially limiting any vertical movement of the grid with respect to the anode and cathode.

The heater 17 may comprise a hairpin of filamentary resistance material, coated, if desired,

with an insulating layer to insulate it from itself and from the cathode or provided with sleeves of insulating material or other means to keep it from touching the cathode. The filament may be positioned within the cathode and the lower ends may be bent outwardly as. indicated and welded to two short support rods 38 sealed adjacent the center of the press 13 for that purpose.

The support rod 36 which is attached to the anode may be connected by means of a wire 39 to the anode base terminal 40, While the post 35 which is attached by means of the strap 32 to the cathode, may be connected by means of the wire 41 to the cathode terminal 42 at the baseof the tube. In like manner the grid support 3'7 may be connected by means of the wire 43 to the grid base terminal 44 and the two filament support rods 38 may be connected by means of Wires 45 to the two filament terminals 46 at the base of the tube.

Thus described the invention is substantially the same as that described and illustrated in my application above referred to. As explained above however, I have found that in heating the elements during the exhausting process in an automatic machine, the temperature of the filament is raised so high that it heats the cathode above the vaporization point thereof with the results as above mentioned. I have found that 105 if I can conduct the heat fast enough away from the ends of the cathode that this disadvantageous result is not encountered and hence, I provide a strap 47 at the top of the cathode which passes around the end thereof and is preferably welded to the top of the upright 35. Thus when the temperature of the cathode is raised the heat may flow outwardly toward the ends and to the rod 35 through the strap 32 at the bottom and the strap 37 at the top, cooling the cathode surhciently to prevent its disintegration and thereby preventing the formation of a conducting film of metal upon either of the insulators 22 and 23.

In addition to forming a heat conducting path 120 the strap 47 also anchors the upper end of the post 35 so that it can have no movement in the slot 27 in the upper insulator and this increases the rigidity of the structure.

While the strap 32 at the bottom of the oathode is secured to the insulator 23 by means of the fingers 33 these fingers may be dispensed with when the strap 4'? at the top is used because the latter strap prevents any downward movement of the cathode while the former at 130, the bottom prevents any upward movement and both straps are anchored to the post 35 which prevents rotation of the cathode. However, if desired, the fingers may be used on the bottom strap and fingers may also be provided on the strap 47 for anchoring this strap to the upper insulator 22 in a manner similar to the way the strap 32 is anchored to the lower insulator 23.

Many modifications of the invention may be resorted to without departing from the spirit 140 thereof, and I not therefore, desire to limit myself to what has been shown and described except as such limitations occur in the appended claims.

What I desire to claim by Letters Patent is:

1. In an electron device a tubular anode, an insulating plate attached to one end of said anode, an insulating plate secured on the other end of said anode, a cathode adjacent said anode and supported thereby, a transverse strap of metal secured to said cathode and in contact with said first insulator plate, and a transverse strap of metal secured to said cathode and in contact with said second insulating plate, whereby heat is conducted laterally away from the ends of said cathode.

2. In an electron device an anode, an insulating plate attached to one end of said anode, an insulating plate attached to the other end of said anode, a tubular element extending between said insulating plate adjacent said anode, a rod extending outside of said anode and substantially parallel therewith, and a strap connecting one end of said tubular element and said rod and in contact with said plate.

, 3. In an electron device a tubular anode, a substantially flat insulating plate attached to one end of said anode, a substantially flat insulating plate attached to the other end of said anode, a grid within said anode and having a portion thereof extending through openings in said insulator plates, a tubular cathode within said grid and extending through openings in said insulator plates, a rod spaced from said anode and extending substantially parallel thereto, a metal strap attached to one end of said cathode and to one end of said rod, and a second metal strap connecting the other end of said cathode with the other end of said rod, said straps respectively contacting with the surface of the adjacent plate.

4. In an electron device a press, a pair of relatively long support rods sealed in said press and extending substantially parallel to each other in spaced relation, a pair of spaced apart insulators transversely positioned with respect to said rods, said rods extending through holes in said insulators, a tubular anode positioned between said insulators, means to secure said insulators to said anode, one on each end thereof, means to rigidly secure said anode to one of said support rods, a tubular grid within said anode and having portions thereof cooperating 'with openings in said insulating plates to hold said grid in position, a tubular cathode within said grid and protruding through openings in said insulator plates whereby said cathode is maintained in position, a metal strap secured 'on one end of said cathode and attached to the other of said rods, a second metal strap connecting the other end of said rod and the other end of said cathode, a relatively short support rod sealed in said press, means to connect said support rod to said grid, and means to heat said cathode, said straps respectively contacting with the surface of the adjacent plate.

5. In an electron device a tubular element, two apertured insulation plates, one attached to an end of said conductor, a conductor connecting said plates having ends each projecting through one of said apertures, a second conductor connecting said plates and having ends each projecting through another of said apertures,

and metal straps joining the projecting ends of '7. In an electron device a pair of spaced apart insulators, a tubular electrode element mounted between said insulators, and means having substantially circumferential surface contact with said element to conduct heat away'from both ends of said element, said means being also in contact at either end of the tubular element with said insulators.

8. In an electron device a pair of spaced apart insulators having openings therein, a tubular electrode element extending between said insulators and protruding through the openings therein, and means having substantially circumferential contact with said electrode element and relatively high heat conductivity to conduct heat away from the ends of said element, said means having contact with the insulators at either end.

9. In an electron device a pair of spaced apart insulating members, said insulating members having openings therein, a tubular electrode element extending between said insulators and protruding through said openings, a second electrode element adjacent said first element and attached to said insulators, and means having substantially circumferential contact with said electrode element and relatively high heat conductivity to conduct heat away from the ends of said first element, said means having contact with said insulating members.

10. In an electron device an electrode element, a second electrode element adjacent the first element, means to insulatingly support the ends of said elements from each other, and means having substantially circumferential contact with said first named electrode element and also contact with said insulating means to conduct heat away from the ends of one of said elements.

11. In an electron device a pair of spaced apart insulating plates, an electrode element p0- sitioned between said plates, a cathode positioned between said plates, means in contact with said insulation plates and with substantial circumferential engagement therewith to conduct heat away from said cathode, and means to heat said cathode.

12. In an electron device an anode, a cathode adjacent said anode, a grid between said anode and cathode, insulating means at one end of said anode, grid, and cathode to support the ends thereof in spaced relation to each other, insu- 125 lating means at the other end of said elements to support the other ends of said elements in spaced relation to each other, means having relatively high. heat conductivity in contact with one of said insulators and attached to said cath- 130 ode with substantially circumferential engagement therewith to conduct heat away from that end of said cathode, and means having relatively high heat conductivity adjacent the other insulator and attached to the other end of said cath- 135 ode with substantially circumferential engagement therewith to conduct heat away from that end thereof.

13. In a vacuum tube a unitary element structure comprising a pair of insulating plates, an 140 anode extending between said plates and connected thereto whereby said plates are rigidly held with respect to said anode, a grid extending between said plates and supported thereby, a cathode extending between said plates and pass- 45 ing through an opening through each of said plates, an arm attached to said cathode and extending outwardly therefrom and adjacent one of said plates, means on said arm to secure said arm to said plate, and an arm attached to said 150 grid and extending substantially parallel to one of said plates and cooperating therewith to prevent, movement of said grid laterally of said plate.

14. In a vacuum tube a unitary element structure comprising a pair of insulating plates, an anode extending between said plates and having portions abutting against said plates, fingers on said anode extending through openings in said plates and bent over against said plates to hold said plates in position, a grid adjacent said anode, a support for said grid extending through openings in said plates, an arm attached to said grid support and extending outwardly along the surface of one of said plates, an angular extension on said arm extending through an opening in said plate, a second arm attached to the end of said cathode and extending outwardly along the surface of said plate, and a plurality of fingers attached to said arm and adapted to pass through openings in said plate and to be bent over at the end of said plate to hold said arm against said plate.

15. In a vacuum tube a pair of spaced apart insulating plates, a tubular anode-extending between said plates, fingers on the end of said anode passing through openings in said plates and extending at right angles to: hold said plates upon the ends of said anode, a tubular cathode within said anode and passing through openings in said plates, an arm secured to one end of said cathode and extending outwardly adjacent the surface of one of said plates, fingers on said arm adapted to pass through an opening in said plate and be bent over to hold said arm against said plate, and a longitudinal flange on said anode and extending outwardly in the opposite direction to said arm.

16. In a vacuum tube a pair of spaced apart insulating plates, a tubular anode extending between said plates, fingers on the end of said anode passing through openings in said plates and extending at right angles to hold said plates upon the ends of said anode, a tubular cathode within said anode and passing through openings in said plates, an arm secured to one end of said cathode and extending outwardly. adjacent the surface of one of said plates, fingers on said arm adapted to pass through on opening in said plate and be bent over to hold said arm against said plate, a longitudinal flange on said anode and extending outwardly in the opposite direc-v tion to said arm, a press, a cathode connector mounted in said press, and an anode connector mounted in said press, said connectors being spaced apart sufficiently to contact with said cathode arm and said anode flange when said element structure is positioned upon said press, said insulators having openings to receive said anode connector and said cathode connector.

WALTER LOUIS KRAHL. 

